As a hydraulic brake system for a vehicle, there is known a system disclosed in the following Patent Literature, for instance. The disclosed system is configured such that a pressure of a working fluid supplied from a high-pressure-source device is adjusted by a pressure-increase linear valve and a pressure-decrease linear valve and a brake device provided for a wheel generates a braking force whose magnitude depends on the pressure adjusted by the linear valves, namely, an adjusted pressure. In this system, in view of a risk that a sufficient braking force is not obtained in a case where leakage of the working fluid occurs in the brake device or in fluid passages that communicate with the brake device, some measures are taken to cope with the fluid leakage.